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Finding the Fourth Proportional to 840.55, 1,259.98 and 320.42

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Solution

The fourth proportional to 840.55, 1,259.98 and 320.42 is: 480.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.55 : 1,259.98 = 320.42 : x
  2. Step 2: Convert to fraction form
    840.55/1,259.98 = 320.42/x
  3. Step 3: Cross multiply
    840.55x = 1,259.98 × 320.42
  4. Step 4: Simplify right side
    840.55x = 403,722.79
  5. Step 5: Solve for x
    x = 403,722.79/840.55
  6. Step 6: Final answer
    x = 480.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.